Rapid population growth, urbanization, industrialization, and climate change are the key drivers causing serious water pollution around the globe. Considering the impacts of these key drivers, this study employed the Water Evaluation and Planning (WEAP) simulation tool to simulate the future water quality in a nearly 60-km stretch of the Hau River, Vietnam. The business-as-usual (BAU) scenario; scenarios with measures (WM), i.e., wastewater treatment plants (WWTPs) for treating 75% (WM75) and 100% (WM100) of total future wastewater generated; and the optimistic scenario (WM_Opt., i.e., WM100 + additional treatment plants for river water (RWTPs)) to achieve the desired water quality, were applied to simulate the future Hau River water quality for the year 2030. Result suggests that the average values of biochemical oxygen demand (BOD), total coliform (TC), nitrate (NO₃⁻), and phosphate (PO₄³⁻) in the wet season of 2030 under BAU scenario will be increased by 16.01%, 40.85%, 30.49%, and 20.22%, respectively, in comparison to those of the current year, i.e., 2018. In the dry season, these rates will be increased by 27.80%, 65.94%, 31.05%, and 20.64%, respectively. Under the scenario with measures (WM75 and WM100), although the Hau River water quality was improved but did not reach the desired limits, especially for BOD and PO₄³⁻ levels in the downstream region. However, under the WM_Opt. scenario, the average simulated values of both BOD and PO₄³⁻ will be significantly declined by 76.53% and 63.96%, respectively as compared to the current situation and help to achieve river water quality under class A. This study is providing policy-relevant scientific information, vital for sustainable water resource management.

人口快速增长、城市化、工业化和气候变化是导致全球严重水污染的主要驱动因素。考虑到这些关键驱动因素的影响，本研究采用了水评估和规划 (WEAP) 模拟工具来模拟越南后河近 60 公里长的河段的未来水质。一切照旧 (BAU) 场景；有措施的情景 (WM)，即污水处理厂 (WWTP) 处理未来产生的废水总量的 75% (WM75) 和 100% (WM100)；和乐观情景（WM_Opt.，即 WM100 + 额外的河水处理厂 (RWTPs)）以达到预期的水质，被应用于模拟 2030 年未来的后河水质。结果表明平均值生化需氧量 (BOD)，BAU 情景下 2030 年雨季的₃ ⁻ )和磷酸盐 (PO ₄ ³⁻ ) 将分别比当年增加 16.01%、40.85%、30.49%和 20.22%，即, 2018. 在旱季，这些费率将分别提高27.80%、65.94%、31.05%和20.64%。在采取措施（WM75 和 WM100）的情景下，虽然后河水质有所改善，但并未达到预期限值，尤其是下游地区的BOD 和 PO ₄ ³⁻水平。但是在WM_Opt下。情景，BOD 和 PO ₄ ³⁻的平均模拟值 与当前情况相比，将分别显着下降 76.53% 和 63.96%，并有助于实现 A 类河流水质。本研究提供了与政策相关的科学信息，对可持续水资源管理至关重要。